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Message-ID: <YUoCneU8zveJ54Kv@myrica>
Date: Tue, 21 Sep 2021 17:04:45 +0100
From: Jean-Philippe Brucker <jean-philippe@...aro.org>
To: Vivek Gautam <vivek.gautam@....com>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
iommu@...ts.linux-foundation.org,
virtualization@...ts.linux-foundation.org, joro@...tes.org,
will.deacon@....com, mst@...hat.com, robin.murphy@....com,
eric.auger@...hat.com, kevin.tian@...el.com,
jacob.jun.pan@...ux.intel.com, yi.l.liu@...el.com,
Lorenzo.Pieralisi@....com, shameerali.kolothum.thodi@...wei.com
Subject: Re: [PATCH RFC v1 05/11] iommu/virtio: Add SVA feature and related
enable/disable callbacks
On Fri, Apr 23, 2021 at 03:21:41PM +0530, Vivek Gautam wrote:
> Add a feature flag to virtio iommu for Shared virtual addressing
> (SVA). This feature would indicate the availablily path for handling
> device page faults, and the provision for sending page response.
In this case the feature should probably be called PAGE_REQUEST or
similar. SVA aggregates PF + PASID + shared page tables
Thanks,
Jean
> Also add necessary methods to enable and disable SVA so that the
> masters can enable the SVA path. This also requires enabling the
> PRI capability on the device.
>
> Signed-off-by: Vivek Gautam <vivek.gautam@....com>
> ---
> drivers/iommu/virtio-iommu.c | 268 ++++++++++++++++++++++++++++++
> include/uapi/linux/virtio_iommu.h | 1 +
> 2 files changed, 269 insertions(+)
>
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 3da5f0807711..250c137a211b 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -18,6 +18,7 @@
> #include <linux/of_iommu.h>
> #include <linux/of_platform.h>
> #include <linux/pci.h>
> +#include <linux/pci-ats.h>
> #include <linux/platform_device.h>
> #include <linux/virtio.h>
> #include <linux/virtio_config.h>
> @@ -26,6 +27,7 @@
>
> #include <uapi/linux/virtio_iommu.h>
> #include "iommu-pasid-table.h"
> +#include "iommu-sva-lib.h"
>
> #define MSI_IOVA_BASE 0x8000000
> #define MSI_IOVA_LENGTH 0x100000
> @@ -37,6 +39,9 @@
> /* Some architectures need an Address Space ID for each page table */
> DEFINE_XARRAY_ALLOC1(viommu_asid_xa);
>
> +static DEFINE_MUTEX(sva_lock);
> +static DEFINE_MUTEX(iopf_lock);
> +
> struct viommu_dev_pri_work {
> struct work_struct work;
> struct viommu_dev *dev;
> @@ -71,6 +76,7 @@ struct viommu_dev {
>
> bool has_map:1;
> bool has_table:1;
> + bool has_sva:1;
> };
>
> struct viommu_mapping {
> @@ -124,6 +130,12 @@ struct viommu_endpoint {
> void *pstf;
> /* Preferred page table format */
> void *pgtf;
> +
> + /* sva */
> + bool ats_supported;
> + bool pri_supported;
> + bool sva_enabled;
> + bool iopf_enabled;
> };
>
> struct viommu_ep_entry {
> @@ -582,6 +594,64 @@ static int viommu_add_pstf(struct viommu_endpoint *vdev, void *pstf, size_t len)
> return 0;
> }
>
> +static int viommu_init_ats_pri(struct viommu_endpoint *vdev)
> +{
> + struct device *dev = vdev->dev;
> + struct pci_dev *pdev = to_pci_dev(dev);
> +
> + if (!dev_is_pci(vdev->dev))
> + return -EINVAL;
> +
> + if (pci_ats_supported(pdev))
> + vdev->ats_supported = true;
> +
> + if (pci_pri_supported(pdev))
> + vdev->pri_supported = true;
> +
> + return 0;
> +}
> +
> +static int viommu_enable_pri(struct viommu_endpoint *vdev)
> +{
> + int ret;
> + struct pci_dev *pdev;
> +
> + /* Let's allow only 4 requests for PRI right now */
> + size_t max_inflight_pprs = 4;
> +
> + if (!vdev->pri_supported || !vdev->ats_supported)
> + return -ENODEV;
> +
> + pdev = to_pci_dev(vdev->dev);
> +
> + ret = pci_reset_pri(pdev);
> + if (ret)
> + return ret;
> +
> + ret = pci_enable_pri(pdev, max_inflight_pprs);
> + if (ret) {
> + dev_err(vdev->dev, "cannot enable PRI: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void viommu_disable_pri(struct viommu_endpoint *vdev)
> +{
> + struct pci_dev *pdev;
> +
> + if (!dev_is_pci(vdev->dev))
> + return;
> +
> + pdev = to_pci_dev(vdev->dev);
> +
> + if (!pdev->pri_enabled)
> + return;
> +
> + pci_disable_pri(pdev);
> +}
> +
> static int viommu_init_queues(struct viommu_dev *viommu)
> {
> viommu->iopf_pri = iopf_queue_alloc(dev_name(viommu->dev));
> @@ -684,6 +754,10 @@ static int viommu_probe_endpoint(struct viommu_dev *viommu, struct device *dev)
> if (ret)
> goto out_free_eps;
>
> + ret = viommu_init_ats_pri(vdev);
> + if (ret)
> + goto out_free_eps;
> +
> kfree(probe);
> return 0;
>
> @@ -1681,6 +1755,194 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args)
> return iommu_fwspec_add_ids(dev, args->args, 1);
> }
>
> +static bool viommu_endpoint_iopf_supported(struct viommu_endpoint *vdev)
> +{
> + /* TODO: support Stall model later */
> + return vdev->pri_supported;
> +}
> +
> +bool viommu_endpoint_sva_supported(struct viommu_endpoint *vdev)
> +{
> + struct viommu_dev *viommu = vdev->viommu;
> +
> + if (!viommu->has_sva)
> + return false;
> +
> + return vdev->pasid_bits;
> +}
> +
> +bool viommu_endpoint_sva_enabled(struct viommu_endpoint *vdev)
> +{
> + bool enabled;
> +
> + mutex_lock(&sva_lock);
> + enabled = vdev->sva_enabled;
> + mutex_unlock(&sva_lock);
> + return enabled;
> +}
> +
> +static int viommu_endpoint_sva_enable_iopf(struct viommu_endpoint *vdev)
> +{
> + int ret;
> + struct device *dev = vdev->dev;
> +
> + if (!viommu_endpoint_iopf_supported(vdev))
> + return 0;
> +
> + if (!vdev->iopf_enabled)
> + return -EINVAL;
> +
> + if (vdev->pri_supported) {
> + ret = iopf_queue_add_device(vdev->viommu->iopf_pri, dev);
> + if (ret)
> + return ret;
> + } else {
> + /* No other way to handle io page fault then */
> + return -EINVAL;
> + }
> +
> + ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
> + if (ret)
> + iopf_queue_remove_device(vdev->viommu->iopf_pri, dev);
> +
> + return ret;
> +}
> +
> +static void viommu_endpoint_sva_disable_iopf(struct viommu_endpoint *vdev)
> +{
> + struct device *dev = vdev->dev;
> +
> + if (!vdev->iopf_enabled)
> + return;
> +
> + iommu_unregister_device_fault_handler(dev);
> + iopf_queue_remove_device(vdev->viommu->iopf_pri, dev);
> +}
> +
> +static int viommu_endpoint_enable_sva(struct viommu_endpoint *vdev)
> +{
> + int ret;
> +
> + mutex_lock(&sva_lock);
> + ret = viommu_endpoint_sva_enable_iopf(vdev);
> + if (!ret)
> + vdev->sva_enabled = true;
> + mutex_unlock(&sva_lock);
> +
> + return ret;
> +}
> +
> +static int viommu_endpoint_disable_sva(struct viommu_endpoint *vdev)
> +{
> + mutex_lock(&sva_lock);
> + viommu_endpoint_sva_disable_iopf(vdev);
> + vdev->sva_enabled = false;
> + mutex_unlock(&sva_lock);
> +
> + return 0;
> +}
> +
> +int viommu_endpoint_enable_iopf(struct viommu_endpoint *vdev)
> +{
> + int ret;
> +
> + mutex_lock(&iopf_lock);
> + if (vdev->pri_supported) {
> + ret = viommu_enable_pri(vdev);
> + if (ret)
> + return ret;
> + }
> + vdev->iopf_enabled = true;
> + mutex_unlock(&iopf_lock);
> + return 0;
> +}
> +
> +int viommu_endpoint_disable_iopf(struct viommu_endpoint *vdev)
> +{
> + if (vdev->sva_enabled)
> + return -EBUSY;
> +
> + mutex_lock(&iopf_lock);
> + viommu_disable_pri(vdev);
> + vdev->iopf_enabled = false;
> + mutex_unlock(&iopf_lock);
> + return 0;
> +}
> +
> +static bool viommu_dev_has_feature(struct device *dev,
> + enum iommu_dev_features feat)
> +{
> + struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
> +
> + if (!vdev)
> + return false;
> +
> + switch (feat) {
> + case IOMMU_DEV_FEAT_IOPF:
> + return viommu_endpoint_iopf_supported(vdev);
> + case IOMMU_DEV_FEAT_SVA:
> + return viommu_endpoint_sva_supported(vdev);
> + default:
> + return false;
> + }
> +}
> +
> +static bool viommu_dev_feature_enabled(struct device *dev,
> + enum iommu_dev_features feat)
> +{
> + struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
> +
> + if (!vdev)
> + return false;
> +
> + switch (feat) {
> + case IOMMU_DEV_FEAT_IOPF:
> + return vdev->iopf_enabled;
> + case IOMMU_DEV_FEAT_SVA:
> + return viommu_endpoint_sva_enabled(vdev);
> + default:
> + return false;
> + }
> +}
> +
> +static int viommu_dev_enable_feature(struct device *dev,
> + enum iommu_dev_features feat)
> +{
> + struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
> +
> + if (!viommu_dev_has_feature(dev, feat))
> + return -ENODEV;
> +
> + if (viommu_dev_feature_enabled(dev, feat))
> + return -EBUSY;
> +
> + switch (feat) {
> + case IOMMU_DEV_FEAT_IOPF:
> + return viommu_endpoint_enable_iopf(vdev);
> + case IOMMU_DEV_FEAT_SVA:
> + return viommu_endpoint_enable_sva(vdev);
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int viommu_dev_disable_feature(struct device *dev,
> + enum iommu_dev_features feat)
> +{
> + struct viommu_endpoint *vdev = dev_iommu_priv_get(dev);
> +
> + if (!viommu_dev_feature_enabled(dev, feat))
> + return -EINVAL;
> +
> + switch (feat) {
> + case IOMMU_DEV_FEAT_IOPF:
> + return viommu_endpoint_disable_iopf(vdev);
> + case IOMMU_DEV_FEAT_SVA:
> + return viommu_endpoint_disable_sva(vdev);
> + default:
> + return -EINVAL;
> + }
> +}
> static struct iommu_ops viommu_ops = {
> .domain_alloc = viommu_domain_alloc,
> .domain_free = viommu_domain_free,
> @@ -1695,6 +1957,9 @@ static struct iommu_ops viommu_ops = {
> .get_resv_regions = viommu_get_resv_regions,
> .put_resv_regions = generic_iommu_put_resv_regions,
> .of_xlate = viommu_of_xlate,
> + .dev_feat_enabled = viommu_dev_feature_enabled,
> + .dev_enable_feat = viommu_dev_enable_feature,
> + .dev_disable_feat = viommu_dev_disable_feature,
> };
>
> static int viommu_init_vqs(struct viommu_dev *viommu)
> @@ -1811,6 +2076,8 @@ static int viommu_probe(struct virtio_device *vdev)
> goto err_free_vqs;
> }
>
> + viommu->has_sva = virtio_has_feature(vdev, VIRTIO_IOMMU_F_SVA);
> +
> viommu->geometry = (struct iommu_domain_geometry) {
> .aperture_start = input_start,
> .aperture_end = input_end,
> @@ -1902,6 +2169,7 @@ static unsigned int features[] = {
> VIRTIO_IOMMU_F_PROBE,
> VIRTIO_IOMMU_F_MMIO,
> VIRTIO_IOMMU_F_ATTACH_TABLE,
> + VIRTIO_IOMMU_F_SVA,
> };
>
> static struct virtio_device_id id_table[] = {
> diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h
> index 53aa88e6b077..88a3db493108 100644
> --- a/include/uapi/linux/virtio_iommu.h
> +++ b/include/uapi/linux/virtio_iommu.h
> @@ -17,6 +17,7 @@
> #define VIRTIO_IOMMU_F_PROBE 4
> #define VIRTIO_IOMMU_F_MMIO 5
> #define VIRTIO_IOMMU_F_ATTACH_TABLE 6
> +#define VIRTIO_IOMMU_F_SVA 7
>
> struct virtio_iommu_range_64 {
> __le64 start;
> --
> 2.17.1
>
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